用Intents打開新頁面Android

當我點擊我的ListView上的ListItems使用Intents時，我正嘗試切換到新頁面。不過，我不斷收到錯誤：用Intents打開新頁面Android

Unfortunately, ToDoApp has stopped

我不太知道如何使用調試器還沒有，但是這是我到目前爲止所。

public class ToDoActivity extends Activity { 
    private ArrayList<String> todoItems;   
    private ArrayAdapter<String> todoAdapter; // declare array adapter which will translate the piece of data to teh view 
    private ListView lvItems; // attach to lsitview 
    private EditText etNewItem; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_to_do); 
     etNewItem = (EditText) findViewById(R.id.etNewItem); 
     lvItems = (ListView) findViewById(R.id.lvItems); // now we have access to ListView 
     //populateArrayItems(); // call function 
     readItems(); // read items from file 
     todoAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, todoItems); //create adapter 
     lvItems.setAdapter(todoAdapter); // populate listview using the adapter 
     //todoAdapter.add("item 4"); 
     setupListViewListener(); 
     setupEditItemListener(); 
    } 

    private void launchEditItem() { 
     Intent i = new Intent(this, EditItemActivity.class); 
     startActivity(i); 
    } 

    private void setupEditItemListener() { // on click, run this function to display edit page 
     lvItems.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       launchEditItem(); 
      } 
     }); 
    } 

    private void setupListViewListener() { 
     lvItems.setOnItemLongClickListener(new OnItemLongClickListener() { 
      @Override 
      public boolean onItemLongClick(AdapterView<?> adapter, View item, int pos, long id) { 
       todoItems.remove(pos); 
       todoAdapter.notifyDataSetChanged(); // has adapter look back at the array list and refresh it's data and repopulate the view 
       writeItems(); 
       return true; 
      } 
     }); 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.to_do, menu); 
     return true; 
    } 

    public void onAddedItem(View v) { 
     String itemText = etNewItem.getText().toString(); 
     todoAdapter.add(itemText); // add to adapter 
     etNewItem.setText(""); //clear edit text 
     writeItems(); //each time to add item, you want to write to file to memorize 
    } 

    private void readItems() { 
     File filesDir = getFilesDir(); //return path where files can be created for android 
     File todoFile = new File(filesDir, "todo.txt"); 
     try { 
      todoItems = new ArrayList<String>(FileUtils.readLines(todoFile)); //populate with read 
     }catch (IOException e) { // if files doesn't exist 
      todoItems = new ArrayList<String>(); 
     } 
    } 

    private void writeItems() { 
     File filesDir = getFilesDir(); //return path where files can be created for android 
     File todoFile = new File(filesDir, "todo.txt"); 
     try { 
      FileUtils.writeLines(todoFile, todoItems); // pass todoItems to todoFile 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 
}

我想運行函數setupEditItemListener()將開闢到我的新Activity，但它沒有這樣做。有人能幫我指出我出錯的地方嗎？謝謝！

控制檯輸出：

[2013-12-07 20:39:05 - ToDoApp] ------------------------------ 
[2013-12-07 20:39:05 - ToDoApp] Android Launch! 
[2013-12-07 20:39:05 - ToDoApp] adb is running normally. 
[2013-12-07 20:39:05 - ToDoApp] Performing com.example.todoapp.ToDoActivity activity launch 
[2013-12-07 20:39:05 - ToDoApp] Automatic Target Mode: using existing emulator 'emulator-5554' running compatible AVD 'NexusS' 
[2013-12-07 20:39:05 - ToDoApp] Uploading ToDoApp.apk onto device 'emulator-5554' 
[2013-12-07 20:39:05 - ToDoApp] Installing ToDoApp.apk... 
[2013-12-07 20:39:05 - ToDoApp] Success! 
[2013-12-07 20:39:05 - ToDoApp] Starting activity com.example.todoapp.ToDoActivity on device emulator-5554 
[2013-12-07 20:39:06 - ToDoApp] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.example.todoapp/.ToDoActivity }

的logcat：

12-08 16:03:33.854: D/dalvikvm(2012): Not late-enabling CheckJNI (already on) 
12-08 16:03:33.884: D/dalvikvm(2012): GC_FOR_ALLOC freed 37K, 6% free 2641K/2808K, paused 0ms, total 0ms 
12-08 16:03:33.894: I/dalvikvm-heap(2012): Grow heap (frag case) to 3.307MB for 635808-byte allocation 
12-08 16:03:33.914: D/dalvikvm(2012): GC_FOR_ALLOC freed 2K, 6% free 3259K/3432K, paused 19ms, total 19ms 
12-08 16:03:33.924: D/AndroidRuntime(2012): Shutting down VM 
12-08 16:03:33.924: W/dalvikvm(2012): threadid=1: thread exiting with uncaught exception (group=0xb2ec4648) 
12-08 16:03:33.924: E/AndroidRuntime(2012): FATAL EXCEPTION: main 
12-08 16:03:33.924: E/AndroidRuntime(2012): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.todoapp/com.example.todoapp.ToDoActivity}: java.lang.RuntimeException: Don't call setOnClickListener for an AdapterView. You probably want setOnItemClickListener instead 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.ActivityThread.access$600(ActivityThread.java:141) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.os.Handler.dispatchMessage(Handler.java:99) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.os.Looper.loop(Looper.java:137) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.ActivityThread.main(ActivityThread.java:5103) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at java.lang.reflect.Method.invoke(Method.java:525) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at dalvik.system.NativeStart.main(Native Method) 
12-08 16:03:33.924: E/AndroidRuntime(2012): Caused by: java.lang.RuntimeException: Don't call setOnClickListener for an AdapterView. You probably want setOnItemClickListener instead 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.widget.AdapterView.setOnClickListener(AdapterView.java:773) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at com.example.todoapp.ToDoActivity.setupEditItemListener(ToDoActivity.java:52) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at com.example.todoapp.ToDoActivity.onCreate(ToDoActivity.java:41) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.Activity.performCreate(Activity.java:5133) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175) 
12-08 16:03:33.924: E/AndroidRuntime(2012):  ... 11 more

來源

2013-12-08 Liondancer

現在是一個適當的時間來學習如何使用調試器！ –

@RickFalck你會知道調試器教程的好資源嗎？ – Liondancer

不是。我從以前的語言/平臺調試工具的經驗使我很容易看到下一個如何工作。它們都有相同的基本方式來設置斷點，並在斷點處停下時查看變量。 Android有LogCat，這很像使用System.out。在java控制檯程序中使用println（）來輸出數據而不是跟蹤它。 –

也許考慮

setOnItemClickListener(..)

您的通話將這些工具的匿名監聽器類更換呼叫

setOnClickListener(..)

，所以這一變化可能需要改變監聽接口名稱，方法簽名。

你可以看到一個建議，在

RuntimeException的做到這一點的堆棧跟蹤：不要叫setOnClickListener了一個AdapterView。你可能想要setOnItemClickListener而不是

來源

2013-12-09 03:33:39

老兄，你創建一個自定義函數，並在這些功能你寫的ListView聽衆。只是通過叫他們這些聽衆不會開火。

只需在沒有自定義功能的onCreate()中編寫聽衆。它會工作。此外，你的應用程序停止。請養成堆棧跟蹤以查看錯誤的習慣。也許這是一個空行指針例外。它通常是應用程序崩潰的原因。

來源

2013-12-08 04:21:33

如果我註釋掉'launchEditItem'和'setupEditItemListener'，我的應用程序可以工作在能夠刪除'LongClick'列表中的項目並且能夠將項目添加到列表中。我試圖用Intents創建類似的東西。我不太確定跟蹤堆棧的位置。我在網上查了一下，我被告知它在控制檯中，但它並沒有給我提供太多的內容，但是我會在問題 – Liondancer

上發佈它的夥計logcat窗口是堆棧跟蹤。再次運行您的應用。通過執行相同的方案使其崩潰。看到LogCatWindow。複製RED行（段落）中的所有錯誤。將其粘貼在代碼標記 –

我發佈了LogCat，但我不知道如何獲得... 11個更多的顯示 – Liondancer

答案只在你的logcat中。不要讓一個習慣要經過的logcat： -

12-08 16:03:33.924: E/AndroidRuntime(2012): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.todoapp/com.example.todoapp.ToDoActivity}: java.lang.RuntimeException: Don't call setOnClickListener for an AdapterView. You probably want setOnItemClickListener instead

使用setOnItemClick聽衆，開始你的活動您正在使用列表項的錯誤監聽它

來源

2013-12-09 04:32:51

。它必須有我「onItemClickListener」

private void setupEditItemListener() { 
lvItems.setOnItemClickListener(new OnItemClickListener() { 

    @Override 
    public void onItemClick(AdapterView<?> parent, View view, int position, 
      long id) { 
     // TODO Do anything you want to do here... 
    } 
}); 
    }

來源

2013-12-09 06:07:37 Prakash

用Intents打開新頁面Android

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